<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>JS的引入案例</title>
</head>

<body>
    Hello World <br>
</body>
<!-- 1 内部JS -->
<script>
    //在网页body中填充内容
    document.write("Hello 内部JS <br/>")
</script>
<!-- 2 引入外部JS -->
<script src="js/first.js"></script>

</html>